1. Field of the Invention
The present invention provides a system and method for stereoscopic display, and more particularly, a system and method for time-multiplexed autostereoscopic display.
2. Descriptions of the Related Art
Stereoscopic display has become a hot topic of research in recent years. The primary principles of a stereoscopic display are as follows: a display device feeds images, which presents different viewing angles for the left eye and the right eye and results in an image with depth in viewer's brain when the two images with the same image contents but different parallaxes are viewed by the two eyes respectively. Thus, the resulting image is perceived to be stereoscopic.
There are various technologies based on the aforesaid principles of the stereoscopic display, one of which is called a “system for time-multiplexed autostereoscopic display”.
With reference to FIG. 1, the “system for time-multiplexed autostereoscopic display” was invented by Professor Adrian Travis of Cambridge University. The display system 9 has a cathode ray tube (CRT) 91, two lenses 92 and a shutter or slit array 93.
The CRT 91 can project a ray (image), which is then transmitted through the lenses 92 to impinge on the slit array 93. The slit array 93 has a plurality of slits 931, which can be turned on sequentially, but not simultaneously. In more detail, at a specific time point, only one slit 931A of the slits 931 is turned on while the other slits 931B are turned off.
Although the ray impinges on all the slits 931 of the slit array 93, only a small part of the ray can pass through the only turned-on slit 931A while the other part of the ray is blocked by the slits 931B that are turned off. The CRT 91 adjusts the intensity of the ray projected by each pixel thereof according to different positions of the turned-on slit 931A (i.e., the CRT 91 adjusts the displayed image). Therefore, when the slits 931 are turned on in turn, each pixel of the CRT 91 will emit rays of different intensities and different directions outwards from the slit array 93.
By emitting the rays of different intensities and different directions, the display system 9 can simulate a light, which appears to be emitted by an object in the space, to form a three-dimensional (3D) virtual image of the object that can be viewed by a viewer 94 positioned in front of the slit array 93.
The system for time-multiplexed autostereoscopic display may be applied in medical treatments so that medical workers can observe 3D images of patients' organs through the display system. The system for time-multiplexed autostereoscopic display may also be applied in video communication so that the 3D images of both parties can be seen by each other.
However, a problem with the system for time-multiplexed autostereoscopic display is that “the 3D image outputted has an insufficient brightness”. The reason is as follows: at each time point, only a small part of the ray generated by the CRT can pass through the only turned-on slit while a major part of the ray is blocked by the slit array. If the slit array has one hundred slits, then only one hundredth (i.e. 1%) of the ray can be outputted by the display system each time while ninety-nine hundredths (i.e. 99%) of the ray is wasted.
Another problem with the system for time-multiplexed autostereoscopic display is the requirement of particularly high frame rate. The reason is as follows: to prevent the viewer who is viewing the 3D image from perceiving the flickering of the 3D image, the display system needs to output at least sixty 3D images within a second; however, the CRT needs to output the same number of display images as that of the slits each time when one 3D image is outputted, so the images of at least “sixty times the number of the slits” must be generated by the CRT within a second.
If the number of the slits is one hundred, then the CRT needs to generate at least six thousand images within a second and each of the slits is tuned on for only one six-thousandth (i.e. 1/6000) second before being turned off. This has a great influence on the service lives of both the CRT and the slits.
Accordingly, an urgent need exists in the art to provide a system or method for a time-multiplexed autostereoscopic display which can improve at least one of the aforesaid shortcomings.